MIPS: Add support for XPA.

Add support for extended physical addressing (XPA) so that
32-bit platforms can access equal to or greater than 40 bits
of physical addresses.

NOTE:
      1) XPA and EVA are not the same and cannot be used
         simultaneously.
      2) If you configure your kernel for XPA, the PTEs
         and all address sizes become 64-bit.
      3) Your platform MUST have working HIGHMEM support.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9355/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 5 insertions, 0 deletions

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 48dfb9de853d..ac96817d1f99 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -516,6 +516,10 @@ static inline unsigned int decode_config5(struct cpuinfo_mips *c)
                 c->options |= MIPS_CPU_MAAR;
         if (config5 & MIPS_CONF5_LLB)
                 c->options |= MIPS_CPU_RW_LLB;
+#ifdef CONFIG_XPA
+        if (config5 & MIPS_CONF5_MVH)
+                c->options |= MIPS_CPU_XPA;
+#endif
 
         return config5 & MIPS_CONF_M;
 }
diff --git a/arch/mips/kernel/proc.c b/arch/mips/kernel/proc.c
index 130af7d26a9c..298b2b773d12 100644
--- a/arch/mips/kernel/proc.c
+++ b/arch/mips/kernel/proc.c
@@ -120,6 +120,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
         if (cpu_has_msa)        seq_printf(m, "%s", " msa");
         if (cpu_has_eva)        seq_printf(m, "%s", " eva");
         if (cpu_has_htw)        seq_printf(m, "%s", " htw");
+        if (cpu_has_xpa)        seq_printf(m, "%s", " xpa");
         seq_printf(m, "\n");
 
         if (cpu_has_mmips) {